The development model, top left, of
the gas chromatograph-mass spectrometer was the first step toward
spacecraft hardware. After a breadboard model, completed in October
1971 to perfect functioning of the instrument, designers worked on
weight, size, and modifications to integrate it into the lander. The
mockup, top right, is 35 centimers wide. Finally, the flight GCMS is
tested and prepared for its long journey through space to investigate
Mars.